If I was a hiring manager with the actual time to do this I think what I would likely do is come up with a series of thought experiments and some actual technical tests for the candidate. Probably I would try to pick things that I did not (off the top of my head) know the answer to and exactly how to do it. And then I might try to go through with the candidate and see their thought process through the whole thing while also volunteering some of my thought process to try to solve it together.

The point would not even be to try to necessarily solve the problem itself - more just to see how I got along with them. Of course some people might freeze up when asked to do this, but I think that happens in any higher pressure interview environment. And if I do not know the solution off the top of my head either and am obviously even struggling in some parts myself I think that takes a ton of the pressure off of them to be a wizard that can solve it in the moment.